Exemplary embodiments of the invention relate to a device for interior illumination for a vehicle. The interior illumination in the vehicle can be used in principle for different purposes. A light cone for illuminating a predetermined limited spatial volume in the vehicle is typically generated for reading illumination. The reading illumination in this case illuminates a working space, for example for reading or writing. For ambient illumination, the entirety of the interior or portions of the interior of the vehicle are preferably evenly illuminated. Furthermore, self-luminous design elements in the vehicle interior are known which make various lighting arrangements possible.
DE 10 2012 015 039 A1 discloses an interior lamp for a vehicle comprising a lamp unit for forming the reading light and an additional lamp for forming an ambient illumination. The two lamp units are controlled by the same control unit depending on sensor signals containing information on the object to be illuminated. In this case, the lamp unit that forms the reading light comprises a plurality of light sources, which are preferably LEDs. The control device uses the light intensity of the object to be illuminated, which intensity is detected by a sensor unit, to control the brightness of the light intensity emitted by the lamp unit and the luminous field and to correctly illuminate the object.
A camera is required to control the illumination. There is no provision for different color temperatures or matched illuminances using other light sources.
The term “ambient illumination” is in the present case understood to mean illumination of the entire vehicle interior or of parts of the vehicle interior (for example, the rear region of the vehicle interior), which illumination is as even as possible and also diffuse. The ambient illumination therefore regulates virtually the entire brightness in the vehicle interior or at least of large contiguous regions of the vehicle interior.
The term “reading light” is in the present case understood to mean illumination, which is as even as possible, of a severely limited partial volume of the vehicle interior (in particular, the illumination of the reading or working region for a vehicle occupant). The brightness of the reading light is advantageously selected so as to facilitate fatigue-free working or reading.
Exemplary embodiments of the invention are directed to a device and a method for interior illumination for a vehicle which provide adaptive, flexible and favorable illumination of the vehicle interior.
A first aspect of the invention relates to a device for interior illumination for a vehicle. The device comprises one or more arrays, which in turn comprise a plurality of light sources. The surface density of the light sources on the array is preferably greater than or equal to one light source per square centimeter. The array preferably has a surface in the range of 10 cm2 to 1000 cm2. The array consists of a plurality of individual light sources; that is to say, at least two individual light sources form the array. In this case, a plurality of individual light sources is preferably used. In the simplest case, the array is designed as a linear array, so that the individual light sources are arranged in a row. The array is preferably two-dimensional, i.e., planar, the individual light sources being arranged in a 2D grid form. The light sources are preferably arranged in one plane on the array. The spacing of the light sources from one another on the array can be constant over the entire array or vary over the array. The light sources of the array are designed in such a way that an ambient illumination and a reading illumination can be generated inside the vehicle by means of this array.
The device also comprises a lamp unit provided in addition to the array, by means of which lamp unit exclusively an ambient illumination within the meaning of the aforementioned definition can be generated inside the vehicle. Matrix illumination of the interior is thus not possible. As for the arrays, brightness and color temperature can also be changed for the additional lamp unit.
The device lastly comprises a control unit for controlling the light sources in the arrays and the additional lamp unit. In this case, the control unit is designed to adjust in order to selectively control individual light sources in the array and to adjust the brightness and a variety of color temperatures in the array.
The control unit is in this case designed and configured to implement three control modes (first mode, second mode, third mode). In the first mode, the light sources are controlled in such a way that exclusively a reading illumination is generated inside the vehicle by the array. In the second mode, the light sources of the array and the additional lamp unit are controlled in such a way that exclusively an ambient illumination is generated inside the vehicle. In the third mode, the first and the second mode are simultaneously activated by the control unit in order to simultaneously generate an ambient illumination and a reading illumination.
The disclosed device is suitable for illumination of the interior of various types of vehicles. The vehicle may be, for example, a passenger car or a minibus. The array consists of a plurality of individual light sources; that is to say, at least two individual light sources form the array. In this case, a plurality of individual light sources is preferably used. In the simplest case, the array is designed as a linear array, so that the individual light sources are arranged in a row. The array is preferably two-dimensional, i.e., planar, the individual light sources being arranged in a 2D grid form.
The term “inside the vehicle” or “vehicle interior” is in the present case understood in particular to mean the internal space of the vehicle that can be used by vehicle occupants. In passenger cars, the rear region of the vehicle interior is of particular interest. The vehicle can be a passenger car, heavy goods vehicle, bus, rail vehicle, watercraft (for example a ship), submarine vehicle, or an aircraft.
The additional lamp unit is advantageously arranged so as to be locally separated from the array and its individual light sources. The additional lamp unit advantageously evenly illuminates the entire rear region. The additional lamp unit advantageously generates a greater luminous flux based on the aperture angle of the beam path than the light sources of the array. The additional lamp unit advantageously comprises one or more LED elements, which each provide a higher luminous power than the individual light sources of the array.
One advantageous effect of the invention is that passengers in the rear region of a vehicle can use more favorable illumination conditions, in particular higher illuminances as a result of adding together the illuminances of the arrays and the additional lamp unit.
According to an advantageous embodiment, the lamp unit is arranged on a vanity mirror in the rear region of the vehicle or in the region of the vanity mirror in the rear region of the vehicle.
By way of example, a vanity mirror is attached to the rear side of the backrest of the driver's seat or of the passenger seat. In this case, the line of vision of a passenger sitting on the rear bench seat falls toward the vanity mirror. In this respect, the passenger on the rear bench seat can view themselves in the vanity mirror when the additional lamp unit is active, the light of the additional lamp unit being reflected from the vanity mirror at a minimum angle from the face of said passenger and with respect to the mirror. In the case of a minibus having a plurality of rear bench seats, a vanity mirror of this kind can for example also be attached at locations other than the rear side of the backrest of the driver's seat or passenger seat.
According to a further advantageous embodiment, the additional lamp unit is arranged between two rear seats in the rear region of the vehicle.
The expression “between two rear seats” can in this case refer to the immediate space for example between the portions of the backrest of the rear bench seat. However, the additional lamp unit can also be arranged on the roof of the vehicle, the expression “between the rear seats” then describing the position with respect to a lateral direction of the vehicle. An additional lamp unit can thus be placed above the rear seats and at the height of the boundary between two rear seats or two portions of the rear bench seat.
A further advantageous embodiment is characterized in that a plurality of the light sources of the array have a different emission characteristic, and the control unit is designed and configured in such a way that an emission characteristic of the array can be adjusted by selecting and activating individual light sources of the array. The term “emission characteristic” (also referred to as “directional characteristic”) denotes in the present case the angular dependence of the intensity of the emitted luminous radiation.
By changing the emission characteristic of the array, the beam angle of the array can be adjusted, the beam angle typically defining the angle at which the emitted light intensity corresponds to 50% of the maximum light intensity (luminous intensity).
Advantageously, at least two of the individual light sources of the array are different. For example, the color temperature and/or the light color and/or the emission characteristic of the respective light sources can be different from one another. In this case, the array comprises a plurality of light sources, of which at least two have differing light beam angles. As a result of there being a plurality of light sources having beam angles that differ from one another, a main direction of the light beam direction of the array, that is to say the beam angle of the array, can be adjusted by specifically activating particular light sources. If, for example, four light sources point further upwards than four other light sources, an average main light beam direction of the array, which main light beam direction tends to point in the direction of the light sources directed upwards, can be achieved by turning on four of the light sources directed further upwards and turning on two of the light sources directed further downwards, without exploiting the upper maximum angle of the main light beam direction of the array. Depending on the number of individual light sources and the differences thereof with respect to the emission characteristic, a plurality of main light beam directions (beam angles of the array) can thus be generated. The beam angle of the array can in this case advantageously be continuously or gradually varied.
A further advantageous embodiment involves an optical element for beamforming being connected downstream of one or more of the light sources of the array in the light beam direction of these light sources. An optical element of this kind can, for example, comprise one or more lenses and a variable aperture. An aperture angle of a light cone, focusing of the beam path or a direction of the beam path that is generated by the array can thereby be adjusted.
Selecting and activating individual light sources of the array can facilitate targeted selective illumination (matrix illumination) of the interior. As a result, the reading light cone can, for example for the reading light, be freely positioned in terms of the position, size and shape thereof, without the use of mechanically moved parts.
An advantageous embodiment of the invention involves adjusting a luminous flux generated by the light sources and/or a color temperature and/or an illumination region generated by the array inside the vehicle.
An advantageous embodiment of the device involved adjusting a brightness generated by the light sources and/or a color temperature can be adjusted. By way of example, a color temperature of 3,000 Kelvin is conventional, which has a warm white hue. Higher color temperatures of, for example, 4,000 Kelvin are also conceivable, which represent a light color between warm white and neutral white, tending toward a daylight white. 6,000 Kelvin is also conceivable for a cold white light. Furthermore, individual light sources can either emit light in a variety of colors or individual light sources can each have a color that is however different from the other individual light sources. By specifically mixing individual light sources, light can be adjusted so as to have a different color temperature.
According to a further embodiment, the light sources of the array comprise at least one or more LEDs. In this case, the abbreviation LED refers to a “light-emitting diode.” In order to generate different color temperatures, a light source of the array comprises, in each case, at least two or more LEDs, which emit light of different color temperatures. A light source advantageously comprises two to four LEDs.
Furthermore, individual light sources can either emit light in a variety of colors or individual light sources can each have a color that is however different from the other individual light sources. The first case can be comparable to an RGB pixel, this pixel generating the colors red, green and blue and it being possible for this pixel to represent a variety of colors in additive color mixing.
White light is mixed as follows: To this end, the color mixture should be made using white LEDs. Warm white LEDs and cold white LEDs are then used and mixed in order to adjust the color temperature of the white light.
According to a further embodiment, the control unit is designed in such a way that a luminous flux or brightness generated by the additional lamp unit and/or a color temperature can be adjusted.
Both the array together with its light sources and the additional lamp unit can therefore preferably be adjusted in terms of the light color and brightness thereof. The control unit is therefore preferably designed in such a way that the brightness of the light sources of the array, the color temperature of the light sources of the array, and the brightness and/or the color temperature of the additional lamp unit can be adjusted.
The term “luminous flux” describes an energy per time unit, that is to say an amount of light per time that originates from the additional lamp unit. As for the individual light sources, the color temperature can also be changed for the additional lamp unit. The control unit can in this case adjust the color temperature of the beam path of the additional lamp unit by specifically activating or mixing individual light sources that emit light in different colors. A variety of color temperatures can therefore be adjusted. The brightness of the additional lamp unit can also be adjusted. This can be achieved, for example, by adjusting the electrical voltage applied to the additional lamp unit or by adjusting the current. In the case of alternating current, the additional lamp unit can also be dimmed by cutting the phase. The additional lamp unit can preferably be dimmed, irrespective of the type of power supply, positioning or other conditions.
Both the array together with its light sources and the additional lamp unit can therefore preferably be adjusted in terms of the light color and brightness thereof. The control unit is therefore preferably designed in such a way that the luminous flux of the light sources of the array, the color temperature of the light sources of the array, and the luminous flux and/or the color temperature of the additional lamp unit can be adjusted.
The light color, color temperature and brightness are advantageously regulated by one or more sensors in the vehicle interior measuring a current illuminance, a current luminous flux and/or a current light color and transmitting these as sensor information to the control unit in order to regulate these parameters to predetermined desired parameters. The light color is adjusted either by directly controlling colored LEDs or by regulating by means of color-sensitive light sensors. A predominant color temperature and illuminance can, for example, be adjusted in the illumination by means of this feedback.
A sensor is advantageously provided for detecting an illuminance in the immediate vehicle surroundings. The measured values of the control unit that are generated by this sensor are advantageously provided and used to regulate the light sources of the array and/or the additional lamp unit. In particular, it is thus possible to adapt the brightness of the ambient illumination and reading illumination generated in the interior to a surrounding brightness predominant outside the vehicle. This adaptation is advantageously achieved automatically.
The control unit is advantageously connected to an input interface, via which a user can adjust parameters such as brightness of the interior illumination, orientation and positioning of the volume illuminated by the reading illumination, and desired light color, as well as select one of the three modes.
According to a further embodiment, the light sources of the array comprise at least one or more LEDs. In this case, the abbreviation LED refers to a “light-emitting diode.” In order to generate different color temperatures, a light source of the array comprises, in each case, at least two or more LEDs which emit different light colors. A light source advantageously comprises three or four LEDs.
A further aspect of the invention relates to a method for interior illumination for a vehicle, comprising: at least one array formed by a plurality of light sources, by means of which array an ambient illumination and a reading illumination can be generated inside the vehicle; an additional lamp unit by means of which exclusively an ambient illumination can be generated inside the vehicle; and a control unit for controlling the light sources and the additional lamp unit in three modes. The control unit is designed in such a way that in the first mode, the light sources are controlled in such a way that exclusively a reading illumination is generated inside the vehicle, that in the second mode, the light sources and the additional lamp unit are controlled in such a way that exclusively an ambient illumination is generated inside the vehicle, and that in the third mode, the first and the second mode are activated simultaneously.
Advantages and preferred developments of the proposed method can be found by conveying, in an analogous and corresponding manner, the embodiments previously made in conjunction with the proposed device.
A further aspect of the invention relates to a vehicle comprising a device as described above and in the following.
Further advantages, features and details can be found in the following description, in which at least one embodiment is described in detail, optionally with reference to the drawings. Parts which are identical, similar and/or functionally identical are provided with the same reference numbers.
The views in the drawings are schematic and not to scale.